Tech­ni­cal Ana­ly­sis of Coun­ter­me­a­su­res against At­tack on XML En­cryp­ti­on - or - Just Ano­ther Mo­ti­va­ti­on for Au­then­ti­ca­ted En­cryp­ti­on

Juraj So­mo­rovs­ky, Jörg Schwenk

In Pro­cee­dings of the SER­VICES Work­shop on Se­cu­ri­ty and Pri­va­cy En­gi­nee­ring, 2012

Ab­stract

At CCS'11 a new cho­sen-ci­pher­text at­tack on XML En­cryp­ti­on has been pre­sen­ted. This at­tack is of high re­le­van­ce, since it al­lows one to de­crypt ar­bi­tra­ry en­cryp­ted XML pay­load by is­suing 14 ser­ver re­quests per byte on aver­a­ge.

In this paper we di­s­cuss se­ver­al coun­ter­me­a­su­res against this at­tack, which have been con­s­i­de­red by dif­fe­rent frame­work de­ve­lo­pers for dif­fe­rent sce­na­ri­os. We ana­ly­ze the sce­na­ri­os and show why these coun­ter­me­a­su­res do not work. The­re­by, we mo­ti­va­te for the ap­p­li­ca­ti­on of au­then­ti­ca­ted en­cryp­ti­on in the XML En­cryp­ti­on spe­ci­fi­ca­ti­on.

Tags: Au­then­ti­ca­ted En­cryp­ti­on, coun­ter­me­a­su­res, Pad­ding Ora­cle At­tacks, Web Ser­vices, XML En­cryp­ti­on